1. Field of the Invention
The present invention relates to an oxy-fuel cutting tip. More particularly, the present invention relates to an oxyacetylene cutting tip formed of a separate tip core and swaged skirt which cooperate to form gas outlet passages.
2. Description of the Related Art
Oxy-fuel cutting tips such as oxyacetylene cutting tips must be capable of mixing and discharging oxyacetylene gas and preheat oxygen which combust to preheat a workpiece to be cut, and also must be capable of discharging cutting oxygen during a cutting operation. Conventionally, oxyacetylene cutting tips have been formed from a single piece of copper bar stock. For example, as seen in FIG. 1 a conventional oxyacetylene cutting tip is formed from an annular copper body 202 having a central bore 204 forming a cutting gas passage. This central bore is deep drilled in the body 202. Also deep drilled in the body 202 are passages 206 and 208 for preheat oxygen and acetylene gas mixture, and radial inlet passages 210-216 for feeding gases to the gas passages 206 and 208. Such a tip is inherently costly to produce, primarily due to the requirement for deep drilling operations.
Multi-piece cutting tips have also been known. For example, the multi-piece cutting tips use a tip core such as those seen in FIGS. 2 and 3. The tip core 302 of FIGS. 2 and 3 has a drilled central passage 304 through which cutting oxygen is discharged. Although not shown, a skirt concentrically surrounds the tip core and forms an annular passage through which acetylene gas and preheat oxygen delivered via the drilled passages 306 and 308 mix and flow toward the outlet end 310 of the tip core. Grooves 312 are milled in the tip core near the outlet end 310 and cooperate with the unillustrated skirt to form outlet passages for the preheat oxygen and acetylene gas mixture. However, the need to mill or machine the grooves 312 in the tip core contributes to high manufacturing costs for the cutting tip.
In order to ensure complete combustion of the acetylene gas, it should be thoroughly mixed with the preheat oxygen prior to discharge through the outlet passages.
Conventionally, if such complete combustion were required, it was thought necessary to have a relatively long passage in which the acetylene gas and preheat oxygen mixture are thoroughly mixed prior to discharge from the cutting tip. Canadian patent no. 1053138 disclosed a swirl mix system in which the preheat oxygen is swirled in a torch tubing upstream of the cutting tip and in such a way as to create a vortex and the acetylene gas is mixed with this vortex. While this creates a homogeneous gas mixture in a relatively short travel length, the swirling motion of the resulting mixture interferes with the rapid formation of a laminar gas flow for discharge from the cutting tip. Such laminar gas flow is desirable since a turbulent gas flow will create pressure fluctuations which interfere with flame stability and increases the tendency to flashback since the burning velocity is higher in the turbulent regime.